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1d7n
From Proteopedia
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SOLUTION STRUCTURE ANALYSIS OF THE MASTOPARAN WITH DETERGENTS
Overview
Several complementary NMR approaches were used to study the interaction of, mastoparan, a 14-residue peptide toxin from wasp venom, with lipid, membranes. First, the 3D structure of mastoparan was determined using, 1H-NMR spectroscopy in perdeuterated (SDS-d25) micelles. NOESY experiments, and distance geometry calculations yielded a straight amphiphilic, alpha-helix with high-order parameters, and the chemical shifts of the, amide protons showed a characteristic periodicity of 3-4 residues., Secondly, solid-state 2H-NMR spectoscopy was used to describe the binding, of mastoparan to lipid bilayers, composed of headgroup-deuterated, dimyristoylglycerophosphocholine (DMPC-d4) and, dimyristoylphosphatidylglycerol (DMPG). By correlating the deuterium, quadrupole splittings of the alpha-segments and beta-segments, it was, possible to differentiate the electrostatically induced structural, response of the choline headgroup from dynamic effects induced by the, peptide. A partial phase separation was observed, leading to a DMPG-rich, phase and a DMPG-depleted phase, each containing some mastoparan. Finally, the insertion and orientation of a specifically 15N-labeled mastoparan (at, position Ala10) in the bilayer environment was investigated by solid-state, 15N-NMR spectroscopy, using macroscopically oriented samples. Two distinct, orientational states were observed for the mastoparan helix, namely an, in-plane and a trans-membrane alignment. The two populations of 90%, in-plane and 10% trans-membrane helices are characterized by a mosaic, spread of +/- 30 degrees and +/- 10 degrees, respectively. The biological, activity of mastoparan is discussed in terms of a pore-forming model, as, the peptide is known to be able to induce nonlamellar phases and, facilitate a flip-flop between the monolayers.
About this Structure
1D7N is a Single protein structure of sequence from Vespula lewisii with NH2 as ligand. Full crystallographic information is available from OCA.
Reference
Interaction of mastoparan with membranes studied by 1H-NMR spectroscopy in detergent micelles and by solid-state 2H-NMR and 15N-NMR spectroscopy in oriented lipid bilayers., Hori Y, Demura M, Iwadate M, Ulrich AS, Niidome T, Aoyagi H, Asakura T, Eur J Biochem. 2001 Jan;268(2):302-9. PMID:11168364
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